Chaeles selden



(No Model.) 2 Sheets-Sheet 1.

C. SBLDEN.

MEANS FOR OVERGQMING STATIC DISTURBANGES IN T'ELEG-RAPHY. No. 309,572. Patented Dec. 2 3 1884.

07 Zy/Iis vW/arney:

N. PETERS. Phokn-Lflhngmphcr. Washington. D c.

(No Model.) 2 sheets sh eet 2.

' O. SELDEN.

MEANS FOR OVERGOMING STATIC DISTURBANGES IN TBLEGRAPHY.

No. 309,572. v Patented Dec. 23; 1884'.

iii? 7 if %?.'s 069707422 WM ilnrrnn CHARLES SELDEN, OF BALTIMORE, MARYLAND.

MEANS FOR OVERCOMING STATIC DISTURBANCES IN TELEGRAPHY.

SPECIFICATION forming part of Letters Patent No. 309,572, dated December 23, 1884.

Application filed May 15, 1854. (No model.)

To all whom, it away concern:

Be it known that I, CHARLES SELDEN, a citizen of the United States, and a resident of Baltimore, in the county of Baltimore and State of Maryland, have invented certain new and useful Improvements in Duplex and Multiplex Telegraphy, of which the following is a specification.

My invention relates to apparatus designed for the simultaneous transmission of messages in opposite directions over the same wire, and is designed to obviate the disturbing effects in receiving-instruments accompanying the charge and discharge of the main line, and due to what is commonly termec static charge and discharge.

My invention consists in the combination, with a suitable polarized reading or repeating sounder having an unbiased armature-lever, of suitable means operating simultaneously with the occurrence of the static charge and discharge current to render the local battery for the sounder ineffective upon the latter at the instant of such charge and discharge. By the term unbiased lover I mean one which is free to retain either of its extreme positions until a reversal of current in the local circuit occurs.

The device for rendering the local battery ineffective consists, preferably, of contacts closed by the transmitter at the same station with the sounder, and suitably connected, so as to short circuit the local battery from the sounder; or in place of short-circuiting the battery to render it ineffective proper circuit closing and breaking devices may be arranged to open-circuit the batter r at the instant of the static charge and discharge, the circuit of said battery through said circuit closing and breaking device being at all other times closed. Other arrangements. of circuits and contacts might be used for the purpose. By this plan no movement of the reading or repeating sounder will be produced by the short-circuiting of the local. battery, or by otherwise interrupting its flow in the sounder, a full reversal of the current by the relay being necessary for this purpose, while, moreover, if at the time of the operation of the current-reversing relay-contacts controlling the polarized sounder the battery be short-circuited, no movement of the sounder-lever will be producedin either direction. A partial movement of the relaycontacts, although accompanied by a shortcircuiting of the battery, will likewise be of no effect on the sounder, because its lever is unbiased and is unaffected by mere interruption of current or by changes of tension unaccompanied by change of polarity.

Some of the ways in which my invention may be carried out are shown in the accompanying drawings, in which- Figure 1 illustrates diagrammatically an arrangement of the circuits and apparatus when the invention is applied to a quadruplex telegraph. Fig. 2 illustrates a modified arrangement in which an open-circuiting of the local battery is employed in place of a shortcircuiting of the same.

As the arrangements are purely local in character, I have for the sake of simplicity omitted line-batteries and main and artificial lines.

I indicates the ordinary single-point transmitter of a quadruplex telegraph of any desired kind, and It the receiving-relay at the same station with said transmitter, that is designed to respond to the action of a similar key at the distant end of the line. The relay t is indicated as having the usual double set of coilsone for the main and the other for the artificial lineso that outgoing signals shall produce no effect on the relay-armature.

S indicates a reading or repeating sounder for said relay. The sounder is shown as a polarized sounder composed of a lever, A, magnetized by any suitable means, as usual in the art, and two electro-magnets, (t I), acting upon opposite sides of the lever, and so wound that when a current flows in a given direction in the circuit containing their coils one shall attract and the other repel the lever S, thus throwing the latter against one stop or the other, according to the direction of the current. The lever S is unprovided with spring or other retractor, and if made to swing in a horizontal plane will retain its position against one stop until a reversal of the current in the coils a 1) occurs, when it will be thrown in the opposite direction. After the lever has been brought against one stop, however, a mere interruption of the flow of current in the coils of a b will produce no effect upon it. The reversals of current and opposite movements of the sounder-lever A are produced by the action of the armature-lever .O for relay R, which lever by its movements is made to reverse the direction of flow of a local battery, L B, through the coils a b. For the purpose of producing these reversals a pole-changer of well-known construction, such as shown, may be employed.

E indicates the double fixed stop of said pole-changer; f g, the contact-springs on opposite sides of the stop and tending to make contact therewith, and F a movable contact playing between the springs and carried by the relay-lever O. The coils a b are connected, as shown, to the springs f 9, while opposite polesof the battery are connected, respectively, to the fixed and the movable contact E F. In one position of the lever Cthat is, when uninflueneed by the relay-magnet, and when the parts are in the position shown-the current will flow from battery L B through the coils a I) in a certain direction; but if the lever Cbe drawn forward by the relay, so as to shift the contact of the springs, bringing f into and g'out of contact with stop E, the direction of flow of current in coils a b will be reversed and sounder-lever A will move to its opposite position. Carried by the transmitterlever T is a spring or other suitable contact, H, which is adapted to make momentary connection with a contact, K, both in the upward and downward movement of the transmitter. The contacts H K are so adjusted or arranged that this connection shall take place at the moment the transmitting-eontacts of T place the main or transmitting current to line, and at the instant when, in the reverse movement of the transmitter, the mainline battery is withdrawn from line-that is, at the instants of the static charge and discharge. The contacts K H are, as shown, connected respectively with the opposite poles of the local battery L B, and when in connection form a short circuit for said battery, so that if, at the moment of connection, the relay 1t move the pole-changer controlled by its lever so as to reverse the connection for the battery to the sounder S, no current can flow to said sounder and no movement of the sounder-lever will be produced. This action will obviously take place whether the relay-lever G be against its back stop, under the influence of its rctractor, or against its front stop, under the influence of a signal-current from the distant station.

The general operation would be as follows: Transmitter T being at rest, the contacts K H are out of connection and the readingsoundor is free to respond to signals from the distant station by the reversal of current in its coils, produeedby the pole-changer under the action of relay 1. If while the lever G is against its back stop transmitter T be operated so as to put its battery or section of batteryto line, a false movement forward of the lever C may be produced by the action of the socalled static charge; but as at this instant the local battery L B is short-circuited through the contacts K H no movement of the sounder S will be produced, although the lever 0 may move so as to reverse the contacts of its pole-changer, or put them into such position that the current of battery L B, if it were permitted to flow through them and coils a I), would produce an opposite movement of the sounder-lever A. Similarly, as the transmitter T returns to its normal position, the static discharge, which occurs at the moment the linebattery is disconnected, might produce a false signal in the sounder by drawing forward the lever C, were it not that at such instant the cal battery is short-circuited through the contacts K H. The same action would obviously occur if the transmitter T be operated while the lever C is held against its front stop in re sponse to a signaling-current from the distant station, a false signal on the sounder being prevented by the shortcircuit-ing of the bat tery at the instant that the lever O, by the influence of the static charge or discharge, is permitted to fall back and reverse the contacts, whereby the direction of current in the coils a b is controlled.

T indicates the double contact or polechanging transmitter of a quadruplex system in which reversals of line-current are produced in the operation of transmitting two messages in the same direction.

BF indicates a polarized receiver of the sys tem at the same station with T and S the sounder controlled thereby. The sounder is a polarized sounder, as in the previous case, and the relay controls the same by reversing the direction of current from a battery, L B, through said sounder, by means of pole'changing contacts such as already described, or by any other suitable means. The transmitter T is provided with contacts K H similar to those, K H, of transmitter T, the contacts K '11 serving in similar manner to short-circuit battery L B" at the proper instant of time.

It is obvious that the operation of either transmitter will be accompanied by a static charge and discharge, which will affect both receiving-relays R and may produceafalse signal on the sounders. I therefore propose in practice to connect each set of contacts K H and K H to both local batteries, so that either set will short-circuit the local current from both soundcrs and prevent the false signal. The wires Z l, which connect the shortcircuiting wires of the two batteries, permit such double short-circuiting to take place by the action of either transmitter.

I do not limit myself to any particular form or construction of devices for reversing a current in the sounders, nor to the form or construction of the contacts whereby the local batteries are rendered ineffective at the proper instants, as my invention consists, broadly, in combining with a sounder (reading or repeating) worked by reversals of current through it a set of contacts acting simultaneously with the occurrence of the static charge and discharge in such way as to render the said local battery ineffective upon the sounder.

In Fig. 2 is shown an arrangement of circuits and devices that may be employed for open-circuiting the local battery attheinstant ot' the static charge and discharge. In this case the transmitter-lever, as T, carries two springs or contacts, ti which are insulated from one another and fromthe lever and move in contact with conducting plates or surfaces r r". The plates 0' are each provided with a recess at 0, so chosen that in the movement of the lever T, in putting on and taking 0d the main battery, thesprings shall be brought opposite said recesses at the instant of the static charge and discharge, and circuit between the springs and the curved plates will at such instants be broken. Transmitter T is provided with similar contacts and curved plates. The circuit of local battery L B is made through the plates 1* and springs t" of the two transmitters, as indicated. and local battery L B similarly iinds circuit normally through springs and plates i r, as shown.

From the above arrangements it is obvious that the batteries are rendered ineitectix e at the proper time by simply breaking their circuits,-instead of short-circuiting them, the general operation being in other respects the same as in the case of the devices and circuits shown in Fig. 1.

What I claim as my invention is--- l. The combination of a polarized repeating or reading sounder having an unbiased armature, or one adapted to retain the position in which it is placed by a current of one polarity until a reversal of current occurs, a receiving-relay for reversing the current in said reading-sounder, and a transmitter at the same station with said relay having circuitcontrolling contactsi'or rendering the localbattery circuits for the sounder inoperative at the instant of the static charge and dis charge current.

2. The combination, in a duplex telegraph, ot' a reading or repeating sounder adapted to retain the position in which it is placed by either movement of its relay-lever until an opposite movement of the latter is produced, a transmitter, and local contacts controlled by the latter for rendering thelocal battery of the sounder ineffective at the instant of the static charge and discharge.

3. The combination, substantially as described, of a polarized repeating or reading sounder having an unbiased armature, and two sets of contacts controlling the circuits of said sounder, one set controlled or actuated by the relay and serving to reverse the current in said sounder, and the other set controlled by the transmitter at the same station with the relay and serving to stop the flow of current in the sounder simultaneously with the occurence of the static charge and discharge accompanying the operation of said transmitter.

4. The combination of a polarized repeating or reading sounder whose .armature is unbiased, as described, a relay having circuitcontrolliug points adapted to reverse the current in said sounder, and a set of contacts closed simultaneously with the occurrence of the static charge and discharge for neutralizing any effects that might at'sueh times be produced upon the sounder by the action of the relay under the influence of the static charge and discharge.

The combination, in a duplex or multiplex telegraph, of a repeating or reading sounder having an unbiased armature, as described, and two sets of contacts controlling the circuit thereof, one set actuated by the relay, the other by the transmitting apparatus at the same station with the relay, as and for the purpose described.

6. The combination, with a reading or repeating sounder and contacts and circuits whereby the armature is adapted to retain either of its positions until a reverse movement of the relay occurs, of circuit-controlling contacts actuated by the transmitter at the same station with the relay and serving to close a local circuit simultaneously with the occurrence of the static charge and discharge, whereby the movements of the relay, under the action of said charge and discharge, may be rendered ineffective upon the sounder.

7. The combination, with a polarized reading or repeating sounder having an unbiased armature, of a transmitter at the same station therewith, and controlling-contacts connected with the local circuit of the sounder and ad justed in the manner described to close eir cuit at the instant of the static charge and discharge current.

Signed at New York, in the county of New York and State of New York, this 6th day of May, A. D. 188i.

CHARLES SELDEN.

\Vitnesses:

Tiros. TOOMEY, Gno. C. COITIN. 

